Is it true that blocking detachments executed retreating Soviet soldiers right on the battlefield?

"Having reasoned with those gripped by panic and returned them to their positions, to the trenches, the blocking detachment saved both them and those who had not abandoned their positions from death," wrote Marshal Konstantin Rokossovsky about their work.

The establishment of rear guard units is usually associated with the issuance in the summer of 1942 of Stalin’s Order No. 227, ‘Not a Step Back!’. In reality, blocking detachments of the People's Commissariat of Internal Affairs (NKVD) troops were already operating near the front lines at the very beginning of the war. They caught and rounded up looters and saboteurs, returned straggling soldiers to their units and handed deserters over to military tribunals.

In Fall 1941, blocking detachments were established within the Red Army – they were stationed behind the least resilient units. Their personnel were recruited from the most steadfast fighters, who, at the critical moment, were tasked with supporting their comrades who had faltered in battle.

These small units could not – and did not intend to – force thousands of soldiers into an attack, much less mow them down en masse with machine guns – there is no reliable evidence to support this. Weapons were used selectively only against individual instigators who initiated panic and fled their positions, when it was impossible to restore order by any other means. However, such incidents were thoroughly investigated.

Blocking detachments did not simply hide behind the backs of those fighting; they took part in the battles themselves. For example, in September 1942, during the ‘Battle of Stalingrad’, a blocking detachment of the 62nd Army repelled enemy attacks for four days and held its positions until reinforcements arrived.